30/10/2026
One room’s too hot, another never quite warms up, and turning the thermostat up just makes the hot room hotter.
That’s usually a balancing problem rather than a faulty radiator. Hot water takes the easiest route, so the radiators nearest the boiler tend to get the lion’s share and the ones at the far end of the pipework get what’s left. Balancing evens that out, using the lockshield valve on each radiator.
Balancing isn’t the same as bleeding. Bleeding releases trapped air from one radiator and fixes a cold patch at the top. Balancing adjusts the flow across the whole system and sorts uneven heating between rooms. If you’re doing both, bleed first.
It’s a DIY job on a standard central heating system. Allow a couple of hours or more, and you’ll need two clip-on thermometers and an adjustable spanner. On a conventional boiler system, you’re aiming for roughly 11 to 12°C between the flow and return pipes on each radiator. Condensing boilers are often set up for a wider gap (around 20°C), so check your boiler’s manual first.
Heat pumps run at lower flow temperatures and are sensitive to flow rates, so leave those to your installer.
Full step-by-step guide is in our Advice Centre: How to Balance Radiators: Step-by-Step Guide
